MATH
posted by JOE on .
Suppose that you have a supply of a 25% solution of alcohol and a 75% solution of alcohol. How many quarts of each should be mixed to produce 100 quarts that is 30% alcohol?

.25x+.75(100x)=.30(100)
solve for x 
I solved for x which is 90. what do I do next ?
thanks for your help 
x=how many quart of 25% solution of alcohol
100x=the reminder of quart; or how many quart of 75% solution of alcohol 
thanks